Self-powered ZrO <sub>2</sub> nanofibers/n-Si photodetector with high on/off ratio for detecting very low optical signal
Fatma Yıldırım, Zeynep Orhan, Saba Khalili, Hossein Mahmoudi Chenari, Şaki̇r Aydoğan
Abstract
Abstract In this work, a light-sensitive photodetector based on ZrO 2 nanofibers (NFs) formed onto n-Si derived by the electrospinning technique was reported. According to the I – V measurements in the dark, the ZrO 2 NFs/n-Si has an ohmic current conduction mechanism at low voltages and the SCLC conduction mechanism at medium voltages, while the Fowler–Nordheim tunneling conduction model is dominant at high voltages. The dark current and the rectifying ratio were found to be 9.4 × 10 −10 A (at −1.0 V) and 10 351 (at ±1.0 V), respectively. The shunt resistance ( R sh ) (at −1 V) and series resistance ( R s ) (at +2 V) values were determined as 2.0 GΩ and 5.5 kΩ, respectively from the dark I – V plot. The device was shown to be highly sensitive to light and exhibits self-powering characteristics under illumination. The ON/OFF ratio was about 1.0 × 10 6 at zero-bias (self-powered mode) suggested a good response of the device to the light intensity. The maximum responsivity and specific detectivity were calculated to be 1.44 mA W −1 and 4.5 × 10 8 Jones, respectively. Finally, capacitance and conductance versus bias voltage characteristics of the device were analyzed at various frequencies.